What operation combines the data from two different entities into one table?

The operation that effectively combines the data from two different entities into one table is the Cartesian Product. This operation takes all possible combinations of rows from the first entity with all possible combinations of rows from the second entity. As a result, the output will contain a number of rows equal to the product of the number of rows in each entity.

In relational databases and data manipulation contexts, the Cartesian Product is essential for scenarios where you wish to pair every instance of one dataset with every instance of another dataset. It creates a more comprehensive view by allowing every combination to be analyzed, which can be particularly useful in various analytical scenarios.

The other operations mentioned—selection, set intersection, and set difference—have different purposes and outcomes. Selection narrows down data based on specific criteria, set intersection finds common records in both datasets, and set difference identifies records present in one dataset but not in the other. None of these operations create a comprehensive combined view like the Cartesian Product.